81586197 has 80 divisors (see below), whose sum is σ = 154632192. Its totient is φ = 41640480.

The previous prime is 81586181. The next prime is 81586207. The reversal of 81586197 is 79168518.

It is not a de Polignac number, because 81586197 - 2⁴ = 81586181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81581197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 642348 + ... + 642474.

Almost surely, 2^81586197 is an apocalyptic number.

It is an amenable number.

81586197 is a deficient number, since it is larger than the sum of its proper divisors (73045995).

81586197 is a wasteful number, since it uses less digits than its factorization.

81586197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260 (or 251 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 81586197 is about 9032.5077913058. The cubic root of 81586197 is about 433.7161192936.

The spelling of 81586197 in words is "eighty-one million, five hundred eighty-six thousand, one hundred ninety-seven".